Dual citizenship between the US and Spain is legally possible in practice, though the two countries reach that result from opposite directions. The United States allows its citizens to hold another nationality without penalty. Spain, by contrast, generally requires Americans who naturalize as Spanish to renounce their U.S. citizenship during the oath ceremony. Because the U.S. does not recognize that renunciation as legally effective, many people end up holding both passports, with each country treating them as its own citizen.
What Each Country Says About Holding Both
U.S. law has no provision stripping citizenship from Americans who naturalize elsewhere. Losing U.S. nationality requires a voluntary act performed with the specific intent to relinquish it, usually carried out before a consular officer. A routine oath sworn during a foreign naturalization ceremony doesn’t meet that standard.1U.S. Department of State. Dual Nationality
Spain takes a narrower view. Article 23 of the Spanish Civil Code requires anyone acquiring Spanish nationality through naturalization, residency, or the right of option to renounce their previous citizenship. Article 24 exempts nationals of countries with deep historical ties: Latin American countries, Andorra, the Philippines, Equatorial Guinea, and Portugal.2Ministerio de Justicia. Spanish Civil Code – Article 24 The United States is not on that list. An American naturalizing in Spain has to formally declare renunciation as part of the process.
The mismatch is why dual status exists. Spain records you as having renounced. Washington doesn’t recognize the renunciation. Neither government polices the other’s determination, so you effectively hold both nationalities, with each country treating you as its own within its own borders.
Who Ends Up With Both Citizenships
The cleanest route is birth. A child born in the United States to Spanish parents picks up American citizenship through birthplace and Spanish citizenship through descent, and no renunciation question ever arises because neither country’s naturalization process is triggered.3Punto de Acceso General. Acquiring Spanish Nationality
For adults, the practical path is Spanish naturalization by residency after already holding a U.S. passport. Spain records the renunciation. The U.S. does not, so you keep the American nationality you started with while adding the Spanish one. Inside Spain, officials will treat you as Spanish only. Inside the United States, you remain American.
How Long You Have to Live in Spain
The general requirement for Spanish citizenship through residency is ten continuous years of legal residence, and that’s the number most Americans face.3Punto de Acceso General. Acquiring Spanish Nationality Shorter periods apply to specific categories:
- One year for people born on Spanish territory, spouses of a Spanish national married at least one year with no separation, widows or widowers of a Spanish national, and people born outside Spain to a parent or grandparent who was originally Spanish.
- Two years for nationals of Latin American countries, Andorra, the Philippines, Equatorial Guinea, Portugal, and people of Sephardic origin.
- Five years for people granted refugee status in Spain.
- Ten years for everyone else, including U.S. citizens without any qualifying connection.
Residency has to be continuous and legal throughout. Gaps or unauthorized stretches reset the clock.
What the Application Actually Requires
Once the residency requirement is met, the citizenship application involves testing, documentation, and a final oath. Processing commonly runs well over a year after submission, and some applicants report waits of two to three years.
Two exams are required, both administered by the Instituto Cervantes. The DELE A2 tests basic conversational Spanish. The CCSE covers Spanish government, law, history, and daily life. For Americans learning Spanish as adults, preparation is a real time commitment.
Documentation includes a birth certificate, valid passport, proof of continuous legal residence, criminal record certificates from both the United States and Spain, and evidence of good civic conduct and financial stability.3Punto de Acceso General. Acquiring Spanish Nationality Every U.S.-issued document must carry a Hague Apostille, and only originals with apostilles are accepted; apostilled photocopies don’t count.4Ministry of Foreign Affairs, European Union and Cooperation. Hague Apostille and Legalization Documents not in Spanish must be translated by a sworn translator registered in Spain.5Ministry of Foreign Affairs, European Union and Cooperation. Sworn Translators-Interpreters
The application fee for nationality by residency is approximately €104 in 2026. If the application is approved, you complete the process by swearing or promising allegiance to the King of Spain and obedience to the Constitution and Spanish laws.6Ministerio de Justicia. Spanish Civil Code – Article 23 The choice between a sworn oath and a promise has no legal difference; the sworn version carries religious connotation and the promise does not. This is also where you’re asked to declare renunciation of U.S. citizenship, which, as noted, does not cost you your American nationality under U.S. law.
Keeping Spanish Citizenship Once You Have It
Getting Spanish nationality is one problem. Keeping it is another. Under Article 24 of the Civil Code, Spanish citizens living abroad who voluntarily acquire another nationality can lose their Spanish citizenship after three years unless they act to preserve it.2Ministerio de Justicia. Spanish Civil Code – Article 24
This mostly affects people who were Spanish first and later became American. To keep Spanish nationality, you declare your intention to retain it at the Spanish Civil Registry or the nearest consulate within three years of acquiring the new citizenship.7Ministry of Foreign Affairs, European Union and Cooperation. The Government Extends the Deadline for Spanish Nationality Miss that window and you risk losing Spanish citizenship outright. Keeping consular registration current is the simplest safeguard.
A separate rule affects people who acquired Spanish nationality at birth through descent when both they and their parents were born abroad. They must declare their intention to conserve Spanish nationality at the Consular Civil Registry, typically before turning 21 or within three years of emancipation. That deadline quietly passes people by, and once it passes, the loss is permanent.
Traveling Between the Two Countries
U.S. law requires all U.S. nationals, including dual nationals, to use a U.S. passport when entering and leaving the United States.1U.S. Department of State. Dual Nationality Spain requires its citizens to enter with a Spanish passport or national identity card.8Ministry of Foreign Affairs, European Union and Cooperation. Conditions for Entry Into Spain Carry both when flying between the two: show the U.S. passport at the American end, the Spanish document at the Spanish end. Using a foreign passport for travel to any country other than the United States is fully consistent with U.S. law.
Taxes You Still Owe the United States
This is the part that surprises new dual citizens. The United States taxes its citizens on worldwide income regardless of where they live, so a dual citizen residing in Spain still owes the IRS a return every year reporting global earnings.9Internal Revenue Service. U.S. Citizens and Resident Aliens Abroad Spain also taxes its residents on worldwide income, which means the same earnings can be reached by both tax authorities.
The foreign earned income exclusion cushions the impact. For tax year 2026, you can exclude up to $132,900 of foreign earned income from U.S. taxes if you meet either the bona fide residence test or the physical presence test.10Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026 Foreign tax credits can offset the rest. Many dual citizens work with a cross-border tax professional because the filing rules alone are demanding.
Foreign account reporting is a separate obligation. If your Spanish accounts, combined with any other foreign accounts, exceed $10,000 in aggregate value at any point during the year, you must file FinCEN Form 114, commonly called the FBAR. Form 8938 applies to specified foreign financial assets above higher thresholds: $50,000 for single filers living in the United States or $200,000 for single filers living abroad, with $100,000 domestically or $400,000 abroad for married couples filing jointly.11Internal Revenue Service. Comparison of Form 8938 and FBAR Requirements Penalties for missing these filings can dwarf any tax actually owed.
Social Security Between the Two Countries
The United States and Spain have had a social security totalization agreement in place since April 1, 1988. It addresses two problems: double taxation on social security contributions, and eligibility gaps for workers who split a career between the two countries.12Social Security Administration. Agreement Between the United States and Spain
You pay social security taxes to only one country for the same work. Work in the United States, pay into the U.S. system; work in Spain, pay into the Spanish system. Workers sent temporarily by an employer to the other country for five years or less stay covered by their home country and are exempt from host-country contributions.
For benefits, the agreement lets you combine credits from both systems to meet eligibility thresholds. To use Spanish credits toward a U.S. benefit, you need at least six quarters of U.S. coverage (about a year and a half of work). To use U.S. credits toward a Spanish benefit, you need at least one year of Spanish coverage.12Social Security Administration. Agreement Between the United States and Spain Credits stay on the record in the country where they were earned and are counted in the other only for eligibility. If you qualify for benefits from both systems, the U.S. Windfall Elimination Provision may reduce your American benefit to account for the Spanish pension.